Ametryne, 2-ethylamino-4-isopropylamino-6-methylthio-1,3,5-triazine, is a selective herbicide known since 1960. It has been used in pre- and post-emergence control of broad-leaved and grassy weeds in several types of crops. When used alone; however a high application rate is needed to affect well-developed weeds.
Terbutryne, 2-tert-butylamino-4-ethylamino-6-methylthio-1,3,5-triazine, is a selective herbicide primarily used in winter cereals, as described in Isrel Pat. No. 26950. It is primarily used as a pre-emergence herbicide with only weak post-emergence ability. In addition, when used alone even a rate as high as at 2 kg/ha, it only controls young, immature weeds.
There has been an ever increasing demand for an inexpensive post-emergence herbicide with good action against well developed broad-leaved weeds and especially against such weeds in the flowering stage.